Throughout the gestation period, owners should monitor the bitch's posture, activity, appetite, weight and body changes by observing the bitch on an animal ultrasound machine. Pregnancy can be confirmed by abdominal palpation, imaging and testing for relaxin in the blood. Abdominal palpation requires skilled palpation techniques, and uterine enlargement caused by pregnancy cannot be accurately distinguished from uterine enlargement caused by other processes such as pyometra, which are difficult to detect based on abdominal palpation.

Animal ultrasound examination is an excellent method for pregnancy detection. It also has the advantage of evaluating fetal growth rate and survival rate. It is occasionally possible to identify pregnancy as early as 10 days after mating, and pregnancy can be more reliably detected by animal ultrasound 24-28 days after breeding. At this time, the structure and heart activity of the fetus can be detected in the gestational sac. The fetal heart rate on animal ultrasound ranges from 200-250 beats/min. Fetal movement characteristics of dorsiflexion of the head and extension of the limbs are common after 33-39 days. Fetal maturity and impending fetal death can be evaluated by the development, or lack thereof, of fetal organs. Nonviable fetuses show no cardiac activity and die within 1 day, losing their recognizable shape. After death, the size of the fetus decreases, and it presents an ovoid appearance with heterogeneous echoes.

Although relaxin can be detected 21 days after breeding, it is a more sensitive indicator of when conception occurs 30 days after breeding. High levels of relaxin in serum or plasma can confirm pregnancy. If spontaneous or induced abortion and delivery occur, the concentration decreases or becomes undetectable. Relaxin cannot be detected in pseudopregnant and non-pregnant bitches. veterinary X-ray examination can be performed after about 40 days of pregnancy. The fetal bones have calcified enough to be found on veterinary X-rays. This usually occurs 45 days after the LH peak. Veterinary X-ray examination before delivery is more important. On the one hand, it can know the number of fetuses and detect fetal and placental retention early; on the other hand, it can know whether there are large fetuses or malformed fetuses, and find out problems that may lead to dystocia, so as to prepare for cesarean section early.

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